The European Court of Justice has ruled that time spent by tradespeople travelling to their first customer of the day counts towards the 48-hour working week.

The ruling is a defeat for the UK government.

Plumbers, decorators and carers – and the companies they work for – are among those affected by the ruling.

Some lawyers have suggested that the ruling may have implications as regards adhering to minimum wage laws. Firms may also have to give workers more breaks.

The Working Time Directive means that UK workers are not permitted to work more than 48 hours without signing an opt-out form.

Presently, the guidelines relating to the Directive in the UK stipulate that time spent travelling to work does count towards the limit, but that "normal travel to and from work” and “travelling outside normal working hours” does not.

The ruling focused on a Spanish burglar alarm company called Tyco, which counted its workers' day as beginning when they arrived at a client's premises – which could take up to three hours.

Tyco counted the working day from the time the worker arrived at the first client and the time they left the last one.

The judgment said: “During the necessary travelling time – which generally cannot be shortened – the workers are therefore not able to use their time freely and pursue their own interests. The fact that the workers begin and finish the journeys at their homes stems directly from the decision of their employer to abolish the regional offices and not from the desire of the workers themselves.”

Some employment lawyers have suggested that certain companies may by negatively affected by the ruling. For instance, firms who have bid and won a contract could find their costs rise.

However, for some workers the ruling could also mean either more pay, or the same pay for fewer working hours.

A spokesman for the Business Department said: “We are carefully considering the implications of this judgement”.